A PICTURE IN THE DESERT. 127 



pavement, which echoes like a vault under the horses' hoofs. A 

 plateau of this kind, the small Desert of Mourad, extends from Biskra 

 to the banks of the great salt lake called Chott Mebrir by the Arabs. 

 The gypseous surface is not everywhere exposed : most frequently it is 

 covered by a layer of small rounded pebbles, nearly all quartzose, 

 exhibiting the greatest variety of tints, from the purest white to the 

 most vivid red ; they are mixed with black calcareous stones split on 

 the surface. Whence came these pebbles, which have evidently been 

 ' rolled ' by the waters ? We know not. They are the mysterious 

 witnesses of those grand diluvian torrents which have left the traces 

 of their passage over the surface of the whole earth, though the 

 geologist cannot always discover the mountains or rocks that fur- 

 nished the materials of this diluvium."* 



From the Desert of the Table-lands we must needs make another 

 descent. The town of Batna is situated at the extremity of the lowest 

 of the Atlantean terraces, whose elevation is still some 3300 feet 

 above the level of the sea. To the north-west rise the lofty spires of 

 the colossal chain, with their diadems of cedars sharply defined in black 

 upon the azure of the sky. Loftiest of all soars the Jebel-Tougour, or 

 " Peak of Cedars," reminding the spectator of the Pyrenean crests. 

 Towards the south-east stretch the rounded shoulders of the mountains 

 of the Aures, clad with dense dark forest of oak and pine. In a fold 

 of the mountains lurk the ancient Lambessa and the mouldering ruins 

 of a Roman camp. Four miles to the south of Batna is a large 

 depressed hill, whose base mingles with the table-land, above which it 

 rises only three hundred and thirty feet. This ridge marks the water- 

 shed ; all the streams on the north flowing towards the Mediterranean, 

 and, on the south, gradually disappearing in the arid bed of the 

 ancient Saharan sea. On the frontier line, like a Cyclopean landmark, 

 is planted the Peak of Cedars, while from its loins a torrent issues, 

 and through a deep ravine whirls and leaps and flows towards 

 the desert. Springs, abundant and warm, bubble up through the 

 chalky marls, and take the same direction. Beyond the French mili- 



* Martins " Du Spilzberg an Sahara.'' p. 556. 



